The ideal and usual scenario would hopefully be that you lose with the bookie and win on the exchange. In this case, why would the bookies want to close your account?
Taking value and/or only using their offers.
Here are examples of a few of my accounts:
1. Funds in: £320, Account Balance: £360.
2. Funds in: £540, Account Balance: £720.
3. Funds in: £500, Account Balance: £7,300.
4. Funds in: £900, Account Balance: £0.
5. Funds in: £500, Account Balance: £380
Which one was I banned from?
I was actually banned, so I unable to place any more bets at all, with both 1 and 2 - both made a modest profit.
Bookies 4 and 5 have both made good money out of me. Both have restricted my bets such that I can only place very small wagers.
Bookie 3, on which I've made a large profit, allows me to bet on anything to any level of stakes that I've tried.